This project uses different systems to develop objective and subjective methods to monitor and document opacities in the human lens. We conducted reproducibility studies on the objective systems the Scheimpflug cameras (Zeiss and Oxford) and retroillumination (Neitz and Oxford) cameras. We are studying subjective systems or methods, such as the LOCS II grading system, and the effects of cataracts on visual perception, contrast sensitivity, and glare to identify additional parameters for monitoring cataract presence, progression, or regression. We are now using these systems to study the natural history of various cataracts such as presenile, senile or age-related, steroid-induced, radiation, diabetic, retinitis pigmentosa, gyrate atrophy, and neurofibromatosis 2 cataracts. This study will prepare the way for eventual clinical trials of anticataract drugs.